Friday, October 28, 2011

In the framework of the Seamounts project, a second cruise will be undertaken on board the RRS James Cook between 7 November and 21 December 2011 to explore 5 seamounts that were studied in 2009. Whereas the first cruise focused on the pelagic communities (in the water column), the second one will investigate the benthic assemblages (what lives in, on or close to the seafloor).You can follow the expedition, live from the ship, on the new blog:www.seamountsexpedition.blogspot.com

Participants have worked incredibly hard this last week spending on average 12 hours per day at the world-class facilities generously provided by SAIAB (South African Institute for Aquatic Biodiversity). More than 200 species of fish and 74 species of squid have been identified during the workshop. Additionally, the fish larvae expert Peter Konstantinidis has identified the larval stages of approximately 30 fish species. Although there were far too many samples to work through during this workshop, many of the participants will continue working on them during the ensuing months. Phillip Boersch-Supan and Kirsty Kemp have extracted several hundred biological samples from fishes including stomach contents, otoliths, scales, muscle tissue and brain tissue. These will be used for various studies related to deep-sea fish ecology and physiology. Although the taxonomic data still need to be analysed, the principal scientist, Alex Rogers, expects to find interesting latitudinal differences in the composition of seamount-associated species. Given that this is the first time that these specific seamounts have been studied, this information and the anticipated publications arising from it, should greatly assist in the management of deep-sea ecosystems and allow us to gain a better understanding of how they function ecologically.

Sunday, November 14, 2010

Dr. Vladimir Laptikhovsky has discovered a new species of squid this week belonging to the chiroteuthid group of families. Members of this squid group are generally long and slender and are capable of remarkable bioluminescent displays. Some also have club-like photophores along their arms which are believed to act as lures to attract prey (similar to the anglerfish). More than 70 species of squid have been identified from the seamounts cruise samples thus far. Incredibly, this represents in excess of 20% of the global squid biodiversity! More information regarding workshop findings will be posted tomorrow, the last day of the workshop.

Saturday, November 13, 2010

Picture 1: James Mclaine holds up a ‘humpback blackdevil’ Anglerfish (Melanocetus johnsoni). This fish dangles a bioluminescent light from its forehead in order to lure prey within gulping range. Because this method of feeding is so effective, this fish has little need of swimming muscles and hence the tiny body in relation to its ferocious-looking head.

Friday, November 12, 2010

During the seamounts cruise, specialized nets were regularly deployed to capture zooplankton; tiny creatures that drift in the open ocean and feed predominantly on even smaller plant-like organisms called phytoplankton. Zooplankton comprise several groups of small pelagic animals such as krill, jellyfish and fish larvae and because they are incredibly abundant, form an integral part of the marine ecosystem. Notably, they are the primary food source for a variety of fish and sea mammals including the largest animal on earth; the blue whale. The objectives of the plankton netting survey were primarily to determine species diversity and to estimate abundance around seamounts. Workshop participants Riaan Cedras and Gildas Todinanahary calculate the volume of zooplankton biomass per unit of water trawled over the seamounts (the collection net was fitted with a water-flow meter). Then they extract random samples from each lot (there are too many creatures to count, never mind identify!) and stare through their high-powered microscopes for hours on end to identify the tiny creatures.

Thursday, November 11, 2010

Wednesday, November 10, 2010

Dr. Vladimir Laptikhovsky and Amy Taylor have been examining the Cephalopods (squids) collected during the seamounts cruise in 2009. There are around 300 species of squid that live in the open ocean and larger individuals tend to inhabit progressively deeper waters. Squid are considered the most highly developed of all invertebrates due to their sophisticated nervous and circulatory system, and the fact that they continue to survive in the absence of a hard outer shell. By squirting water out through their siphons, they dart through the water column and catch fish with their tentacles. Using this jet propulsion, they are capable of extreme speeds and some even launch out of the water to ‘fly’ for considerable distances. Their skins are covered in chromatophores which enable them to instantly change color to suite their surroundings and effectively become invisible when they need to. Some species are also able to eject dark ink into the surrounding water to temporarily confuse attacking predators.

In these first three days of the workshop, Vladimir and Amy have already identified approximately 30 different species… two of which have not been collected before in the Indian Ocean!

Picture 1: Dr. Laptikhovsky and Amy Taylor.

Picture 2: Some interesting examples of squid species: A) Onychoteuthis sp: This species is known for its elaborate hooks at the ends of its tentacles which aid it in grasping its prey more securely. B)Pyroteuthis margarititera: Being less streamline, this squid probably relies more on camouflage than speed. C)Pterygioteuthis giardi: The smallest species known to man! D)Cranchia scabra: Although probably quite slow, this squid has some elaborate defense mechanisms. Firstly, it can suck its head and tentacles into its mantel cavity! Next, it injects ink into the cavity and because the mantel is translucent, it is able to match the color of the surrounding water and become invisible. In case all this fails, it sports tiny spikes all along its outside which may irritate the alimentary canals of some predators.

After familiarizing themselves with the laboratory facilities, participants eagerly fell in behind their microscopes and began working through intimidating rows of jars containing fishes, squids, zooplankton and other interesting creatures. Many specimens look similar to each other and scientists have to use elaborate morphological features such as muscle orientation and gut length to differentiate between them. Although no new species have been discovered as yet, the really interesting samples from the colder waters are still to be brought to the workbench during the ensuing week.

First picture: A jar of lanternfishes wait to be scrutinized by Peter Konstantinidis.

Second picture: Hatchetfish (Argyropelecus aculatus). These small (5cm), unusually shaped deep sea fish use bioluminescence (lights on their bodies) to escape predators. By matching the light intensity of their bodies with the light penetrating the water from above, the fish does not appear darker if seen from below and can therefore not be seen by predators.

Friday, November 5, 2010

Almost one full year on, the partners on the SW Indian Ocean seamounts project are ready to start the painstaking task of identifying and cataloguing many of the species sampled in the water column above the six seamounts visited during the 40-day expedition in late 2009.

From the nearly 7000 samples gathered, there are almost certainly going to be previously-undiscovered species as well as new information on where known species congregate, what they eat and how they behave.

The results of this exercise will not only have a scientific interest, but will directly feed into recommendations to help improve conservation and management of Indian Ocean resources and future management of deep-sea ecosystems in the high seas globally.

IUCN, on behalf of all the partners in the project (GEF, ASCLME, EAF-Nansen, ACEP, ECOMAR and the Zoological Society of London) as well as the Total Foundation and Censeam, who have financially supported this workshop, wish the taxonomists success in their endeavours and invite all interested parties to Watch This Space for breaking stories!

Wednesday, December 16, 2009

Tuesday, December 15, 2009

If you are looking for a special Christmas present: Adrift, Tales of ocean fragility is a beautifully illustrated book explaining the fragility of the marine world through the stories of 12 charismatic and fascinating species. Published by IUCN, this book is a joint effort between IUCN's marine team and experts from across the globe to inform and inspire about marine conservation. The story on deepwater corals was written by our Chief Scientist, Dr Alex David Rogers.

You can watch a short video for the book on YouTube here, and buy the book here (in English only).

Monday, December 14, 2009

We have just had our last two trawls of the cruise, this afternoon at Walters Shoal. Although most species looked familiar, there are always some good surprises, and this catch included the first octopus of the expedition, a ghost looking squid and a tiny crustacean larva with impressive spikes. Nous venons de procéder à nos deux dernières pêches, cet après-midi sur Walters Shoal. Bien que la plupart des espèces nous était familière, il y a toujours quelques bonnes surprises, et cette capture a inclu la première pieuvre de l'expédition, un calmar fantôme et une minuscule larve de crustacé avec ses piquants impressionnants.

This makes us realise how close we are to the end of the expedition and to setting foot on land again after several weeks in a floating bumpy habitation. While all of us are looking forward to being back home, it also feels a bit unreal... In order to be connected with the atmosphere that is awaiting us, we have gone through a little redecoration of the ship. Cela nous fait réaliser que nous nous approchons de la fin de l'expédition et de notre premier pied à terre après plusieurs semaines dans une habitation flottante et instable. Si nous nous réjouissons tous de rentrer, cela semble un peu irréel... Aussi, afin de nous connecter à l'ambiance qui nous attend, nous avons entrepris de redécorer un peu le bateau.

Sunday, December 13, 2009

We've left the southwest Indian Ocean Ridge on the 10th of December and steamed northward for two days in order to reach the last seamount that we will study during this cruise, south of Madagascar. The area that we have reached is called Walters Shoal - some sort of enormous underwater plateau, with areas as shallow as 10 meters from the surface! For our investigations, though, we had to go to deeper areas. One of the main reasons we have decided to come here is that the region is known to attract seabirds, and Barau's petrel in particular, that come to feed here at this time of year. We haven't encountered as many seabirds as expected... but at least, we're back in a warm and very pleasant climate. The water is now 21°C.We've been fishing from one to seven AM this morning, and caught some beautiful specimens:

Friday, December 11, 2009

Phytoplankton (microscopic plants) produce half of the oxygen present in the Earth’s atmosphere. Phytoplankton obtain energy through the process of photosynthesis and are therefore restricted to the euphotic zone (depth of water in the ocean exposed to sufficient sunlight to allow for photosynthesis). Phytoplankton forms the base of the aquatic food web and the biomass, composition and distribution strongly influence the nature of oceanic food web dynamics. Without phytoplankton, there would be no life in the oceans... except for the species typically found at hydrothermal vents that do not live off solar energy (have a look at Kirsty’s presentation on the right if you are interested in these strange communities of species).

We found that diatoms formed the dominant phytoplankton group south of 36°S. They include the chain forming species belonging to the genus Pseudonitzschia and Chaetocerus; and large centrics such as Planktoniella and Coscinodiscus (see micrographs below). The stations north of Sapmer Seamount (including Atlantis Seamount) were characterized by low fluorescence, typical of tropical and subtropical water with low levels of nutrients (oligotrophic). The highest fluorescence was measured in the surface waters between the Subtropical Front and the Subantarctic Front around 40°S. In the Subantarctic water the important high latitude flagellate, Phaeocystis sp. (probably P. antarctica), made its appearance in large numbers, although diatoms remained the dominant group.

Thursday, December 10, 2009

Have a look at BBC Earth News to get the latest update on our adventures in the roaring forties, to view a new beautiful picture gallery... and get more answers on why we actually are here! (in English only)

Wednesday, December 9, 2009

We've left the roaring forties to study Melville bank, the last seamount that we will be investigating on the southwest Indian Ocean Ridge. The wind and waves have accompanied us for a few days now, and our fishing night was rather... rock'n'roll! No doubt we have moved further north, as the species are very different from the ones we found on Coral. They are actually very similar to the species encountered on the first seamounts that we have studied - you may recognise these two hatchetfish and the squid?

Monday, December 7, 2009

The kids from the school Baies roses have a great memory of the visit of the Nansen. We invited them for a tour on the vessel while it was at port, in Reunion, on November 10. They’re telling their memories in the December edition of their school journal, accompanied with great drawings! (in French only)

Sunday, December 6, 2009

Coral Seamount was designated a voluntary Benthic Protected Area by the Southern Indian Ocean Deep-Sea Fishers Association because it hosted deep-sea corals. We found that the fauna of the waters surrounding Coral Seamount was different to the other seamounts we surveyed. A species of small cardinal fish (Rosenblattia) was found in deep water at night time. Species of fish usually associated with seamounts were not caught in our pelagic trawls but instead a species of rattail fish was found that occurs in Australia, New Zealand and the Madagascar Ridge. Small silvery lantern fish, Maurolicus were also common in the catches but squids were much less abundant and diverse. The crustacean fauna was also different with some large prawns taken in deeper trawls. We had crossed into quite different waters, much colder and more typical of the Sub-Antarctic regions than the waters north of the sub-tropical front. This also showed in the birds surrounding the ship which were dominated by Southern Ocean species such as wandering albatross, cape pigeons (photo) and prions. The weather also lived up to the fearsome reputation of the roaring forties. After a few days of relative calm we were punished by five days of gale force westerly winds that battered the ship for the last few days work at Coral Seamount and pursued us all the way to Melville Bank, 140nm to the north.

Saturday, December 5, 2009

You remember the cute little fish that looks a bit like a dog from the front. Here it is again, from the side. Any idea what is the link between it and the other fish below?Vous vous souvenez du petit poisson qui ressemble un peu à un chien depuis devant. Voici une photo de son profil. Avez-vous une idée du lien entre ce poisson et celui du dessous?

Kirsty is preparing the transponder, the device that will allow us to find and recover the bones in two years time, when the second cruise is in the area. Kirsty est en train de préparer le transpondeur, cet appareil qui va permettre de retrouver les os dans deux ans, lorsque la seconde expédition sera dans la région.

As a reminder, the purpose is to study the communities that will have colonised the bones. In particular, species of worms named snot flower worms, as we do not know anything about them for the Indian Ocean.

Visitors (as of 26 Nov.)

Follow us on Google Earth / Suivez-nous sur Google Earth

Presentation by Kirsty / Présentation de Kirsty

Lisez l'article du Journal de l'Ile de la Réunion du 11 novembre!

Article

Culinary tip of the day / Bon plan culinaire du jour

Norwegian wafflesTake warm waffles (home made preferably). Top them with the famous Norwegian brown cheese, sour cream, jam (preferably red fruits) and sugar. It is not light... but God it's good! A big thank to our star Signe for preparing them for us!